I don't know if I can prove you wrong, but in my opinion your example of Karl Marx's 200th birthday is misjudged. As far as I know he neither killed nor ordered to be killed anyone. He is no more responsible for people (I assume you have Stalin in mind) twisting his thought than is anyone else. To follow that logic to its conclusion you would also need to express outrage at Christmas, or at the depiction of Jesus on the billboards of churches, because of the deaths occasioned by the Crusades.